Solid rocket propellants typically comprise an oxidizer, a fuel, a variety of additives, and a binder that holds the propellant together. Typical oxidizers include ammonium nitrate, ammonium dinitramide, ammonium perchlorate, potassium perchlorate, and other compounds known in the art. Typical fuels include aluminum powder, boron, and beryllium. Typical binders include nitrocellulose, hydroxy terminated polybutadiene, butadiene terpolymer, polybutadiene-acrylic acid-acrylonitrile, carboxyl terminated polybutyidiene, polyesters, polyethylene glycol, poly tetramethylene glycol and other compounds known in the art. Typical additives include plasticizers such as n-butyl nitratoethyl nitramine, trimethylolethane trinitrate and isodecyl pelargonate, dioctyl adipate; burning rate modifiers such as iron oxide and carbon; combustion stabilizers such as zirconium oxide; anti-oxidants such as n-methyl nitroaniline and 2,2'-Methylene-Bis-(4-Methyl6-Tert-Butylphenol) (available as AO-2246 from American Cyanamid Company, Parsippany, NJ); curing agents such as dimeryl diisocyante, isophorone diisocyanate, and Desmodur.RTM. N-100 (available from Bayer Corporation, Pittsburgh, PA); curing catalysts such as triphenyl bismuth and dibutyltin dilaurate; and acoustic suppressants such as silicon carbide.
Solid rocket propellants can be tailored to specific applications by varying their formulations. Although preliminary work on new formulations can be done in a laboratory with small quantities, testing and large scale demonstrations are typically required before a new formulation is accepted for military or commercial use. As a result, propellant development programs often generate considerable excess inventory of propellant. Production programs also generate excess inventory or off specification material. Finally, excess propellant is generated when rocket motors are periodically remanufactured to replace aging propellant with fresh propellant. In all cases, the excess inventory or off-specification material must be disposed of safely. Historically, open air incineration was the preferred disposal method. Increasingly, however, open air incineration is becoming environmentally unacceptable. Therefore, what is needed in the industry is a solid rocket propellant that can be disposed of with environmentally acceptable techniques.